Al Gore: Crusader against the climate crisis

Lee Cowan interviews the former Vice President and Nobel Prize-winner Al Gore on his second career as an advocate against climate change - and against climate change deniers. Gore, who is featured in a new documentary, "An Inconvenient Sequel: Truth to Power," talks about his efforts to sway President Donald Trump to maintain America's participation in the landmark Paris Climate Agreement, and how advances in energy technology make him more optimistic about changing the course of the Earth's future.